#div0{
    width: 100%;
}
#div0 div{
    float: left;
    height: 100px;
}
#div0 div:nth-child(1){
    background-color: red;
}
#div0 div:nth-child(2){
    background-color: blue;
}
#div0 div:nth-child(3){
    background-color: green;
}
